1. Field of the Invention
The present invention pertains to sleep apnea diagnosis, and, in particular, to a sleep apnea diagnosis system and method.
2. Description of the Related Art
Obstructive sleep apnea (OSA) is a condition that affects millions of people from around the world. OSA is characterized by disturbances or cessation in breathing during sleep. OSA episodes result from partial or complete blockage of airflow during sleep that lasts at least 10 seconds and often as long as 1 to 2 minutes. In a given night, people with moderate to severe apnea may experience complete or partial breathing disruptions as high as 200-500 per night. Because their sleep is constantly disrupted, they are deprived of the restorative sleep necessary for efficient functioning of body and mind. This sleep disorder has also been linked with hypertension, depression, stroke, cardiac arrhythmias, myocardial infarction and other cardiovascular disorders. OSA also causes excessive tiredness.
Various methods have been used to assess whether a patient suffers from OSA. The most comprehensive method is a clinical polysomnogram (PSG), which can diagnose many significant sleep pathologies. However, a PSG requires special hospital or sleep disorder center over-night stays with technicians present to monitor both the equipment and the patient.
Home use devices which measure and combine blood oxygen saturation, pulse rate, airflow, snoring level and head movements have also been used to assess sleep apnea. While these devices are less expensive than a PSG, the devices are still too expensive and obtrusive.
Questionnaires and tests have also been used to assess sleep apnea. However, although questionnaires and tests are cost-free and easy to take, their accuracy in assessing sleep apnea is very limited.
Audio recording has also been used to assess sleep apnea. While audio recording can be accomplished inexpensively and non-obtrusively, the audio recording is sensitive to noise such as ambient noise, a snoring partner, or other noises, thus reducing the accuracy of the technique.
Accordingly, a need exists for improvement in assessing sleep apnea and, for example, for an inexpensive and non-obtrusive way to accurately assess sleep apnea.